1. Field of the Invention
The present invention relates to an electronic control unit for storing vehicle identification information and a vehicle control system including the electronic control unit.
2. Description of the Related Art
Conventionally, a vehicle control system includes electronic control unit (ECU) for controlling various parts of a vehicle. In the ECU, a vehicle identification code (VIN code) unique to each vehicle is stored in a nonvolatile memory to be readable and writable as described, for example, in JP-A-2001-301572. When the ECU is remounted on another vehicle, the VIN code is rewritten. The VIN code is used for identifying the vehicle, for example, when the vehicle is repaired at a dealer. The identification of the vehicle is required for treating the vehicle in the most suitable way.
A stage II of on-board diagnostics regulation (OBD-II regulation) by the California Air Resources Board (CARB) stipulates that failure information of the vehicle is to be stored in a nonvolatile memory. Thus, the failure information is stored in the nonvolatile memory in the ECU. The nonvolatile memory includes, for example, standby random access memory (SRAM) and electrically erasable programmable read-only memory (EEPROM).
The OBD-II regulation further stipulates that all failure information related to emission is to be erased when the VIN code is rewritten. Thus, the emission-related failure information is required to be erased each time when the VIN code in the ECU is rewritten.
In an exemplary method of the conventional art, after the VIN code is rewritten, a failure information erasing order is input from peripheral tool to the ECU. However, in a case where a power switch of the ECU is turned off or the ECU is reset during the erasing of the failure information, the failure information may remain in the ECU.